With nearly all the votes counted, Vucic's Progressive Party won 48 percent of the vote. The allied Socialists who have been ruling in a coalition for the past four years took an additional 11 percent.

The ultra-nationalist pro-Russian Radical Party of Vojislav Seselj, who was recently acquitted of war crimes charges in The Hague, was in third place with 8 percent. Four other parties also reached the 5 percent threshold needed to enter parliament.

"I think this is a historic result, to win more votes in absolute terms, to win in relative numbers, in percentages, more votes than two years ago when we launched very difficult reforms," said Vucic. "I think it is an extraordinary result."

Vucic called the elections two years early, seeking a new mandate to enact tough economic and political reforms demanded by the EU in exchange for moving forward with the regional grouping's membership process.

"Serbia will continue its European journey. We will try to accelerate it. As I said, we will make no compromise there, just as we will zealously continue guarding our traditional friendship and ties with the Russian Federation, the People's Republic of China and many other countries."

Vucic's critics accused him of calling the vote now to avoid public discontent that many predict will occur when those reforms fully impact daily life in the Balkan country of 7.1 million residents.